Generally, in an air conditioner for a vehicle, cooling water which cools an engine of the vehicle to become warm water is circulated through a heating heat exchanger. In the heating heat exchanger, warm water is used as a heat source to heat air, which will be introduced into a passenger compartment of the vehicle to temperature-condition it. In this case, heating of air introduced into the passenger compartment may be insufficient before the temperature of cooling water in the engine is heightened, thus deteriorating a heating capacity of the air conditioner. For example, in a hybrid vehicle or a vehicle having a high-efficiency traveling engine, it is difficult for engine cooling water to supply a sufficient heat amount to a heating operation of the air conditioner.
Therefore, in addition to engine cooling water, another heat source is to be used for a quick-acting heating in the passenger compartment. A quick-acting heating can be provided by a home-used heating device which has a similar construction to a home-used electric fan, for example, referring to JP-U-3078539. The heating device has a halogen lamp (instead of fans and motor) for emitting infrared rays. The halogen lamp is provided with a concave reflector which is big-sized, so that heat of the infrared rays is transferred in a facing direction of the reflection plate to heat the passenger compartment.
However, in this case, the home-used heating device (halogen heater) is too big when being mounted in the vehicle. On the other hand, if the halogen heater is small-sized, the density of the infrared rays from the halogen heater will be heightened to be dangerous.
Because the power of the halogen lamp which is mounted in the vehicle is to be restricted, a sufficient heating sense cannot be provided for the passenger if the irradiation range of the halogen lamp is enlarged. On the other hand, if the infrared rays are converged at a single zone in order to improve the heating sense, a cold/hot difference between the zone and other zones (without being irradiated with infrared rays) will be amplified to deteriorate the comfort.
Moreover, smell may be generated because dust accumulated at a high-temperature portion of the halogen heater is burned, for example, in an initially winter-use of the halogen heater which has not been used in summer.